1. Field of the Invention
The present invention relates to a light-emitting device. More specifically, it relates to an improvement in a light-emitting device of the type in which first and second light-emitting elements are mounted on the same surface side of a substrate portion.
2. Description of the Related Art
In the related art, there has been proposed a light-emitting device in which two light-emitting elements are mounted on one substrate portion in order to ensure a sufficient quantity of light (see Patent Document 1, etc.). As shown in FIG. 1, in accordance with the light-emitting device 1, four internal electrodes 3a, 3b, 3c and 3d are provided on a top surface of a rectangular substrate portion 2 so that light-emitting elements 5 and 6 are mounted on the two internal electrodes 3c and 3d disposed in parallel with each other. The internal electrodes 3a, 3b, 3c and 3d are connected to external electrodes 8a, 8b, 8c and 8d at corners of the substrate portion through leads 7a, 7b, 7c and 7d respectively. The external electrodes 8a, 8b, 8c and 8d are connected to pattern electrode portions 9a, 9b, 9c and 9d as partners in mounting, respectively.
As for techniques in connection with the invention, refer to Patent Document 2, please.
[Patent Document 1] U.S. Pat. No. 6,476,410
[Patent Document 2] JP-A-10-303464
In the light-emitting device 1 in which light-emitting elements are mounted on one substrate portion, the direction of electrical connection of each light-emitting element is fixed. Accordingly, the mounting direction of the light-emitting device 1 relative to the pattern electrode portions 9a, 9b, 9c and 9d is definite. If the connecting direction is reversed, a reverse current flows in each light-emitting element, thereby causing damage of the light-emitting element. Since the substrate portion 2 is shaped symmetrically, there is however possibility that the light-emitting device may be mounted particularly in a wrong lateral direction (rotated by 180° with respective to a correct direction). As a result, the direction of electrical connection of each light-emitting element is reversed to thereby cause damage to the light-emitting device. This brings a poor yield of light-emitting devices.